The present invention relates generally to pattern dyeing of sheet or textile material, for example carpet. More particularly, the invention relates to pattern dyeing of textile material by means of a plurality of controlled liquid dye streams.
The printing of such textile webs, particularly carpets, is well known in the art, and is carried out by a variety of techniques. At the present time most carpet printing is done by techniques more or less analogous to conventional printing techniques, such as rotary printing and screen printing. The use of such traditional carpet printing techniques requires an individual roller or screen for each color of each individual pattern which it may be desired to print. These rollers or screens are typically twelve or fifteen feet wide, and involve great expense both in initial manufacture and in storage.
As an attractive alternative to traditional carpet printing techniques, there is a great deal of interest in controlled dye jet printing of textile materials, particularly carpet, and a number of such machines have been produced. In such machines, plural colored dyes are sprayed or jetted onto the surface of moving textile material. Alternatively, dye jets may move over the surface of a stationary carpet web, with the carpet web intermittently advancing in large increments as is done in traditional screen printing. Generally, such jet printing machines comprise a plurality of dye applicators extending across the path of carpet travel. Each dye applicator comprises a multiplicity of dye outlet tubes or nozzles extending in a line along the applicator traverse to the direction of carpet travel, with the nozzles of each of the applicators being supplied with a different color. Each individual nozzle or jet is controllably activated by suitable electronic, pneumatic or mechanical means to dispense dyes onto the moving textile material under control of a suitable pattern controller. The pattern controller may take any one of various forms. Examples are mechanically, electrically or optically sensed rotating drums or endless webs, coded punch cards, coded magnetic tapes, and various forms of computer based controllers employing high speed random access memories.
A crucial element in such a jet dyeing machine is the means for individually controlling the multiplicity of closely spaced dye streams in a rapid and precise manner. The quality of the finished product, as well as the speed of carpet printing, depend primarily upon the quality of the control means for the individual dye streams. A number of approaches have been previously proposed.
An early example of a jet printing apparatus is disclosed in the McCarthy U.S. Pat. No. 1,873,000 and employs a plurality of magnetically actuated air brushes electrically controlled by a rotating drum having a pattern of insulative and noninsulative areas on the surface thereof which electrical pickup brushes variously contact as the drum rotates, thereby to control individual air brushes in a desired manner.
The Runton U.S. Pat. No. 2,804,764 and the McElveen U.S. Pat. No. 3,393,411 provide examples of fabric printing machines wherein individual solenoid valves are used to selectively and individually control the supply of dye to a plurality of spray nozzles or dye delivery tubes.
The above noted McElveen U.S. Pat. No. 3,393,411 mentions, as an alternative, that portions of the dye delivery tubes may comprise flexible portions, with one or more pinching bars employed to control the flow of dye through the dye delivery tubes.
In another approach, as represented by the Kudlich U.S. Pat. No. 4,141,231, individual electromagnetically operated needle valves control the application of dye to a moving textile web so as to effectively print a pattern thereon. The Moen U.S. Pat. No. 4,157,149 discloses an air pressure operated valve having a similar seating arrangement for the controlled pattern application of fluids such as glue.
A related system, but which does not employ controlled dye streams at all, is disclosed in the Mitter U.S. Pat. No. 4,112,531. In the Mitter system, a plurality of individual mechanically movable dot printing elements actually physically contact the carpet at appropriate points under program control.
Lastly, another particular system for the selective control of dye streams for the purpose of printing carpet employs a plurality of continuously flowing dye streams which are selectively deflected by a stream of air (or by a mechanical deflector) either to permit impingement of the dye stream on a moving inclined web of fabric or carpet, or to cause recirculation of the dye stream to a dye supply reservoir. Although this particular system is fairly complex and expensive, it is in commercial use. This well illustrates the problems involved in the precise control of plural dye streams for carpet dyeing with acceptable response speeds, and the lengths to which the prior art has gone to achieve operation. A large number of patents, as well as publications in the literature, provide details of such systems, and the following are identified merely by way of representative example: Weber et al U.S. Pat. No. 3,443,878; Weber et al U.S. Pat. No. 3,570,275; Stewart, Jr. U.S. Pat. No. 3,969,779; Kline U.S. Pat. No. 3,985,006; Johnson U.S. Pat. No. 4,033,154; and Varner U.S. Pat. No. 4,116,626.
From the above, it will be apparent that rapid and precise selective control of plural dye streams for textile pattern dyeing is a more difficult problem than might appear at first glance. Conventional commercially available solenoid type liquid control valves simply are not adequate. Among the performance requirements for such a dye control system is extreme speed of response to permit precise control of relatively small amounts of dye to form a complex pattern on a textile web moving from twenty to fifty feet per minute, or more. Additionally, the valve and nozzle assembly must be substantially drip free to avoid any unwanted depositing of colored dye on the wrong areas of a carpet pattern. In this connection, it should be noted that in several known prior art systems, to prevent dripping, relatively high viscosity dyes and relatively small nozzles are employed. A drawback to such an approach is that the use of a high viscosity dye requires relatively more dye pressure, up to for example 140 p.s.i., in order to effectively penetrate carpet.
The benefits to be realized through the use of a successful dye jet carpet printing machine are numerous and substantial. For one, the potential speed of printing is far in excess of traditional carpet printing techniques. For example, conventional roller printing techniques are generally limited to 45 feet per minute, and conventional screen printing techniques are generally limited to 20 feet per minute.
Additionally, a dye jet carpet printing machine completely eliminates the necessity to fabricate and store bulky printing rollers or screens. Pattern information can be stored on relatively compact media such as miniaturized drums, photoelectrically sensed drums or webs, magnetic tape, and the like.
A further benefit is the potential ease with which such systems may be programmed for the purpose of printing full sized samples of proposed patterns. Using conventional electronic digital programming techniques, for example employing a CRT display of individual pattern elements with a corresponding keyboard or digitizer tablet data entry device, a pattern designer may in a single day investigate the esthetic qualities of a number of completely different carpet patterns. Such rapid sample production is not possible as a practical matter using conventional printing techniques which require the fabrication of rollers or screens.